1. Field of the Invention
The present invention relates to a pipe lining method, and more specifically relates to a pipe lining method in which, after a lateral pipe has been lined, a start liner is applied to a main pipe in order to line the main pipe.
2. Description of the Prior Art
A method for repairing pipes is known in which, when an underground sewer pipe or other pipe has degraded over time, the pipe is not extracted from the ground, but, instead, a lining is applied to an inner peripheral surface of the pipe to be repaired.
In this method, a pipe lining material is obtained by impregnating a tubular non-woven cloth, whose outer peripheral surface is covered by a highly airtight film, with a curable resin. The tubular pipe lining material is inserted into the pipe while being everted by fluid pressure, and then pressed against the inner peripheral surface of the pipe. The curable resin impregnated in the pipe lining material is then heated and cured to provide the lining for the pipe to be repaired.
A plurality of lateral pipes is connected to the sewer pipe or other pipe (main pipe), and a lining is applied to these lateral pipes by the same method described above. In other words, a lateral pipe lining material composed of a tubular resin absorbing material that has a cured flange on one end, that has an outer surface covered by a highly airtight plastic film, and that is impregnated with an uncured curable resin is guided into the main pipe. The lateral pipe lining material is everted and inserted into the lateral pipe via fluid pressure from the main pipe side toward the ground level in a state in which the flange of the lateral pipe lining material is brought into contact with a peripheral edge of a lateral pipe opening of the main pipe. While the lateral pipe lining material is pressed against an inner wall of the lateral pipe, the curable resin with which the lateral pipe lining material is impregnated is cured to provide the lining for the lateral pipe (Japanese Laid-open Patent Application No. 2000-127241).
Normally, the lateral pipe is lined before lining of the main pipe, and, after the lateral pipe has been lined, the tubular start liner is everted and inserted into the main pipe. The tubular lining material, which is attached to a terminal end of the start liner, is then inserted inside the start liner (Japanese Laid-open Patent Application No. 1996-216256). The start liner mainly prevents ground water and sewage from leaking into the main pipe while the main pipe is being lined, and is used in order to ensure and facilitate the process of lining the main pipe.
In the prior art, after a lateral pipe has been lined, a flange of a lateral pipe lining material is cured and mounted in contact with the peripheral edge of a lateral pipe opening of a main pipe. Therefore, a problem will arise in that, when the main pipe is lined after a start liner has been applied, the bond between the main pipe lining material and the flange of the lateral pipe lining material will be adversely affected by the start liner, the main pipe lining material and the lateral pipe lining material will not be properly joined, water will leak into the pipe from the inadequately connected portion, and defects will occur in the lining.
It is therefore an object of the present invention to provide a pipe lining method in which a lateral pipe lining material and a main pipe lining material can be reliably bonded when a main pipe is lined with a start liner applied thereto after lining of the lateral pipe.